The present disclosure relates to developer conveyance devices, development devices including such a developer conveyance device, and image forming apparatuses including such a development device.
For development devices, a stirring screw is fitted in a developing housing as a developer conveyance device for conveyance of developer. The stirring screw of a development device includes a shaft portion and a plurality of helical pieces, which are joined successively around the shaft portion. The developer is conveyed in the conveyance direction by the stirring screws being driven to rotate in the development housing.
If the adhesiveness of the developer increases due to degradation of the developer, the developer may adhere to the shaft portion of the stirring screw. If the developer adheres to the shaft portion, the shaft portion, in effect, has a larger thickness. As a result, the conveyance performance of the stirring screw decreases. A type of stirring screw does not include a shaft portion at a middle portion in the axial direction in order to obviate such increase in thickness of the stirring screw. In other words, such a stirring screw has a hollow shape. That is, the stirring screw is hollow.